An Overview of Cytomegalovirus Infection in Pregnancy

The objective of this review was to bring to attention cytomegalovirus (CMV) infection during pregnancy, taking into consideration all relevant aspects, such as maternal diagnosis, fetal infection and prevention, prenatal diagnosis, and postnatal prognosis. A literature review was performed regarding adult and congenital infection. General information regarding this viral infection and potential related medical conditions was provided, considering the issues of maternal infection during pregnancy, transmission to the fetus, and associated congenital infection management. Prenatal diagnosis includes maternal serum testing and the confirmation of the infection in amniotic fluid or fetal blood. Additionally, prenatal diagnosis requires imaging techniques, ultrasound, and complementary magnetic resonance to assess cortical and extracortical anomalies. Imaging findings can predict both fetal involvement and the postnatal prognosis of the newborn, but they are difficult to assess, even for highly trained physicians. In regard to fetal sequelae, the early diagnosis of a potential fetal infection is crucial, and methods to decrease fetal involvement should be considered. Postnatal evaluation is also important, because many newborns may be asymptomatic and clinical anomalies can be diagnosed when sequelae are permanent.

Comparison of detection strategies for screening and confirming congenital cytomegalovirus infection in newborns in a highly seroprevalent population: a mother-child cohort study

Background

Universal screening of congenital cytomegalovirus (cCMV) infection is important for monitoring and intervention during critical stages of speech and language development. This study aimed to explore the optimal detection strategy for cCMV infection screening.

Methods

Serum samples from pregnant women and saliva and urine samples from their newborns were collected for the anti-CMV IgG and CMV DNA PCR tests, respectively. The sensitivity, specificity, and predictive values as well as the likelihood ratios of 12 potential screening strategies for cCMV infection, based on tests for saliva, urine, and their combination, were evaluated.

Findings

A total of 6729 pregnant women were enrolled, and the seroprevalence was 98.1%. Among 6350 newborns that were followed up, 49 were defined as having cCMV infection. In the screening test, the CMV DNA positivity rate remained similar from day 0 to day 5, increased slowly from day 6 to day 13, and became high in newborns beyond 13 days of birth. In the confirmatory testing, the positive rates increased significantly beyond day 21. For the 49 newborns with cCMV infection, the proportion of agreement between saliva and urine testing was poor. Upon evaluating alternative screening strategies, using saliva and urine screening with saliva and urine confirmation as the reference strategy, saliva screening with saliva and urine confirmation showed good diagnostic accuracy and feasibility, with sensitivity, specificity, positive predictive and negative predictive values of 85.7%, 100.0%, 100.0% and 99.9%, respectively.

Interpretation

In populations with high seroprevalence, saliva screening with saliva and urine confirmation might be an alternative strategy for screening cCMV infections. The suggested timeframes for screening and confirmation are within 13 (ideally 5) and 21 (ideally 13) days of birth, respectively.

Funding

National Natural Science Foundation of China, National Science and Technology Major Project of China and Merck & Co., Inc., Kenilworth, New Jersey, U.S.A.

Potential Biomarkers for Predicting Congenital Cytomegalovirus Infection

Early diagnosis and treatment of infants with symptomatic congenital cytomegalovirus (CMV) infection may improve neurological outcomes. For this reason, prenatal detection of newborns at high risk for congenital CMV infection is important. A polymerase chain reaction (PCR) assay for CMV DNA in the amniotic fluid is the gold standard for the diagnosis of intrauterine CMV infection; however, amniocentesis is an invasive procedure. Recently, we have found that the presence of CMV DNA in the maternal uterine cervical secretion is predictive of the occurrence of congenital CMV infection in CMV immunoglobulin M (IgM)-positive pregnant women. In contrast, we have suggested that maternal serological screening for primary CMV infection using CMV-specific immunoglobulin G (IgG), the IgG avidity index, or CMV-specific IgM overlooks a number of newborns with congenital CMV infection. We will review current knowledge of the potential biomarkers for predicting congenital CMV infection.

Universal Screening With Use of Immunoglobulin G Avidity for Congenital Cytomegalovirus Infection

Background

The aim of this prospective cohort study was to evaluate the efficacy of maternal screening for congenital cytomegalovirus infection (CCI) using cytomegalovirus (CMV) immunoglobulin G (IgG) and the IgG avidity index (AI).

Methods

Pregnant women underwent screening of CMV IgG and AI measurements. IgG-negative women underwent remeasurement of IgG after educational intervention. Women with an AI ≤45% received further examinations, including measurement of CMV IgM. All newborns received polymerase chain reaction analyses of the urine, and CCI was diagnosed by the detection of CMV-DNA in the urine. Primary infection was defined as an AI <35% and/or positive IgM (>1.20 index). Serum samples from women with an AI >45% were stored, and the IgM levels were measured after delivery. The efficacy of AI and IgM for CCI screening was compared.

Results

A total of 1562 (71.2%) women tested positive for IgG. In this study, 10 newborns with CCI were detected. The presence of infection in 3 newborns from mothers with primary infection was predicted by screening of IgG and AI <35%. However, infection in 7 newborns from women with nonprimary infection could not be predicted by screening of CMV IgG, AI <35%, or IgM. The application of an AI <35% for CCI screening yielded 22.2% sensitivity, 95.0% specificity, 2.5% positive predictive value, and 99.5% negative predictive value and was similar to that of IgM (11.1% sensitivity, 93.2% specificity, 0.9% positive predictive value, and 92.7% negative predictive value).

Conclusions

Maternal screening using CMV IgG and AI can identify pregnancies with CCI from primary infection, but overlooks a number of those from nonprimary infection.

Clinical factor associated with congenital cytomegalovirus infection in pregnant women with non-primary infection

The aim of this nested case-control study was to evaluate clinical factors associated with the occurrence of congenital cytomegalovirus (CMV) infection in pregnant women with non-primary CMV infection. In a cohort study of CMV screening for 2193 pregnant women and their newborns, seven newborns with congenital CMV infection were identified among 1287 pregnant women with non-primary CMV infection that was defined as negative IgM and positive IgG with IgG avidity index >45%. In the 1287 women with non-primary CMV infection, clinical findings and complications were compared between pregnancies with and without congenital CMV infection. Clinical factors associated with the occurrence of congenital CMV infection were evaluated. The birth weight of newborns with congenital CMV infection was less than that of newborns without congenital infection (p < 0.05). Univariate logistic regression analyses demonstrated that threatened premature delivery (OR 10.6, 95%CI 2.0-55.0; p < 0.01) and multiple pregnancy (OR 7.1, 95%CI 1.4-37.4; p < 0.05) were associated with congenital infection. Multivariable logistic regression analyses demonstrated that threatened premature delivery (OR 8.4, 95%CI 1.5-48.1; p < 0.05) was a single risk factor for congenital CMV infection in pregnant women with non-primary CMV infection. This study revealed for the first time that threatened premature delivery was associated with the occurrence of congenital CMV infection in pregnant women with non-primary CMV infection, the pathophysiology of which may be closely associated with CMV reactivation during pregnancy.

Interaction of Immunoglobulin with Cytomegalovirus-Infected Cells

Intravenous immunoglobulin (IVIG) is used to treat or prevent severe viral infection, especially cytomegalovirus (CMV) infections. IVIG was characterized to understand its interaction with CMV-infected cells. IVIG retarded CMV spread and reduced virus yields depending on the neutralizing (NT) antibody titer. Immediate early protein synthesis was reduced by IVIG in 3 to 15 h, and IVIG specifically reduced the ratio of 66/68k protein synthesis among immediate early proteins in an NT antibody-dependent manner between 4 and 8 h after infection, indicating that antigenic modulation of CMV-infected cells by IVIG reduced viral protein synthesis and virus production. The half-life of antibody bound to CMV-infected cells was 3.8 h. NT antibody titers to varicella-zoster virus (VZV) and CMV in IVIG were dose dependently absorbed by cells infected with VZV and CMV, respectively, but the antibody titers to CMV and VZV, respectively, were not affected. NT antibody in 0.3 mL of IVIG (15 mg) was specifically absorbed by 10⁸ CMV-infected cells and 10⁷ VZV-infected cells, suggesting that the NT antibody in IVIG might be inactivated by one-tenth of a similar volume of CMV-infected or VZV-infected cells. Various antiviral activities of IVIG may contribute to control and alleviation of CMV infection.

Cytokine gene polymorphism associations with congenital cytomegalovirus infection and sensorineural hearing loss

Cytomegalovirus (CMV) is the most common viral agent of congenital infections and a leading nongenetic cause of sensorineural hearing loss (SNHL). The host immunologic factors that render a developing foetus prone to intrauterine CMV infection and development of hearing loss are unknown. The aim of this study was to assess the potential associations between the polymorphisms within cytokine and cytokine receptors genes, and the risk of congenital CMV infection, and the hearing outcome. A panel of 11 candidate single nucleotide polymorphisms (SNPs): TNF rs1799964, TNF rs1800629, TNFRSF1A rs4149570, IL1B rs16944, IL1B rs1143634, IL10 rs1800896, IL10RA rs4252279, IL12B rs3212227, CCL2 rs1024611, CCL2 rs13900, CCR5 rs333 was genotyped in 470 infants (72 with confirmed intrauterine CMV infection and 398 uninfected controls), and related to congenital CMV infection, and the outcome. In multivariate analysis, the IL1B rs16944 TT and TNF rs1799964 TC genotypes were significantly associated with intrauterine CMV infection (aOR = 2.32; 95% CI, 1.11–4.89; p = 0.032, and aOR = 2.17, 95% CI, 1.25–3.77; p = 0.007, respectively). Twenty-two out of 72 congenitally infected newborns had confirmed SNHL. Carriers of CT or TT genotype of CCL2 rs13900 had increased risk of hearing loss at birth and at 6 months of age (aOR = 3.59; p = 0.028 and aOR = 4.10; p = 0.039, respectively). This is the first study to report an association between SNPs in IL1B, TNF, and CCL2, and susceptibility to congenital CMV infection (IL1B and TNF) and SNHL (CCL2).

Clinical Significance of IgG Avidity Testing and Other Considerations in the Diagnosis of Congenital Cytomegalovirus Infection: A Review Update

Prompt and accurate laboratory testing of women before or during antenatal days is necessary for detecting humoral immunological responses against cytomegalovirus (CMV) infection and assessing risk of congenital transmission. CMV is the most common viral etiology with the greatest propensity to induce neonatal pathologies. Most healthcare facilities in developing countries rely solely on anti-CMV IgM and IgG assays in diagnosing CMV infections. However, these parameters have some worrisome limitations. This study reviewed the significance of IgG avidity testing as a highly sensitive and specific tool that improves decisions regarding diagnosis of maternal and congenital CMV infections. We conducted this review from relevant published articles using an extensive literature search made through PubMed, Scopus and Google scholar on the concepts of congenital CMV (CCMV) transmission and clinical significance of IgG avidity testing in diagnosis of CCMV infections. Findings from our review revealed that IgG avidity testing in some developed societies was frequently utilized to resolve dilemmas associated with serodiagnosis of CMV infections, however, there is paucity of information in regards to its use in developing countries. The non-inclusion of IgG avidity testing during serological investigations of CMV could be a reason why congenital CMV infections and associated pathologies often go underdiagnosed in developing countries.

Gold magnetic nanoparticle conjugate-based lateral flow assay for the detection of IgM class antibodies related to TORCH infections

In this study, a lateral flow immunochromatographic assay (LFIA) system for the detection of immunoglobulin M (IgM) antibodies, related to TORCH [(T)oxoplasmosis, (O)ther agents, (R)ubella (also known as German Measles), (C)ytomegalovirus, and (H)erpes simplex virus infections], based on gold magnetic nanoparticles, was established. Following modification with poly(methacrylic acid), the gold magnetic nanoparticles conjugated with an anti‑human IgM antibody (μ‑chain specific) to construct a probe. A lateral flow assay device was constructed based on these conjugates. IgM antibodies to four types of pathogens, notably toxoplasmosis, rubella virus, cytomegalovirus and herpes simplex virus type 2, were detected using this device. Compared with commercial colloidal gold‑based LFIA strips, our method exhibited higher sensitivity. No interference with triglycerides, hemoglobin and bilirubin occurred, and no cross‑reactivity was noted among the four pathogens. The gold magnetic nanoparticle‑LFIA strips were used to assess 41 seropositive and 121 seronegative serum samples. The sensitivity was 100% (162/162) and the specificity was 100% (162/162). This method cannot only be used for the detection of TORCH IgM-specific antibodies, but it can potentially be developed for use in the diagnosis of other acute or recently identified autoimmune diseases.

Common childhood viral infections

Infections caused by viruses are universal during childhood and adolescence. Clinicians will regularly care for children and adolescents who present with infections caused by a wide number of viral pathogens. These infections have varied presentations. Many infections may have clinical presentations that are specific to the infecting virus but present differently, based on the age and immunocompetence of the patient. Some children are directly impacted early in their lives when maternal disease results in an in utero infection (cytomegalovirus, rubella virus, or parvovirus B19). Other viruses may infect children in a predictable pattern as they grow older (rhinovirus or influenza virus). Fortunately, many viral infections frequently encountered in the past are no longer extant due to widespread immunization efforts. Recognition of these vaccine-preventable infections is important because outbreaks of some of these diseases (mumps or measles) continue to occur in the United States. Vigilance in vaccine programs against these viral agents can prevent their re-emergence. In addition, an increasing number of viral infections (herpes simplex virus, influenza virus, varicella zoster virus, or cytomegalovirus) can now be successfully treated with antiviral medications. Most viral infections in children result in self-limited illness and are treated symptomatically and infected children experience full recovery. This review will address the epidemiology, clinical presentation, diagnosis, treatment, and prevention of viral infections commonly encountered by the clinician.

Ex vivo model of congenital cytomegalovirus infection and new combination therapies

INTRODUCTION

Congenital human cytomegalovirus (HCMV) infection is a major public health problem due to severe sequelae in the fetus and newborns. Currently, due to their toxicity anti-CMV treatments cannot be administered to pregnant women. We thus developed an ex vivo model of 1(st) trimester placental CMV infection to observe the route of infection across the placenta and to test the efficacy of various new drugs targeting different stages of viral cycle.

METHODS

After validation of the viability of floating villi explants by ELISA β-HCG, the kinetics of placental infection were determined by immunochemistry and qPCR in this ex vivo model. Antiviral susceptibility was determined in vitro using focus reduction assay and by qPCR in the ex vivo model.

RESULTS

The ex vivo model showed viral infection in trophoblasts and mesenchymal space of floating villi. In vitro, antiviral combinations of maribavir with baïcalein or artesunate inhibited viral infection by more than 90%. On the other hand, in ex vivo model, infection was reduced by 40% in presence of maribavir and artesunate. The synergistic effect observed in vitro was not observed ex vivo.

DISCUSSION

This model allowed us to understand the CMV spread in 1(st) trimester floating villi better and to analyze the anti-CMV efficacy and toxicity of new drugs that could be administered to pregnant women, either alone or in combination.

CONCLUSIONS

Such an ex vivo model could be applied to other viruses such as rubella or parvovirus B19 and in new drug development.